1. Field of the Invention
This invention relates to the field of data processing systems. More particularly, this invention relates to the transfer of data via a secure network connection.
2. Description of the Prior Art
The exchange of data via computer networks is becoming increasingly widespread. The adoption of the use of the internet as a way of making network connections is firmly established. The pervasive nature of the Internet has strong advantages in terms of the flexibility it allows and the wide access to data from different sources that is provided. A problem with transferring data via the internet is maintaining the security of that data. The data being exchanged may be confidential, such as credit card or bank details, or might be subject to an unauthorised alteration, such as inserting computer virus code or offensive content into the data being exchanged.
One way of addressing the security issues discussed above is by the use of secure network protocols such as HTTPS. With such protocols, when a client computer wishes to retrieve some data from a server computer, it first establishes a secure connection with that server computer by issuing a HTTPS connection request to the server and waiting for an appropriate Certificate to be returned from the server. Once the secure connection has been established in this way, data can be exchanged across the secure connection in an encrypted form such that its confidentiality may be maintained or to resist tampering with that data. This type of arrangement is well known and has strong advantages.
It is known to provide firewall computers for scanning network traffic for illegal content. A company computer network may typically make its internet connection via a firewall computer such that inbound and outbound traffic to the internet can be scanned for illegal content. A significant problem with this arrangement arises when the client computer and the server computer which are communicating via the firewall computer are connected by a secure link of the type in which the data being transferred is encrypted. As a result of the encryption of the data passing through the firewall computer, the firewall computer is no longer able to scan that data for illegal content. Whilst such secure network connections may be good at maintaining the confidentiality of data being exchanged, they do not in themselves ensure that the data does not contain illegal content, such as offensive material that is banned as a matter of company policy, or malware such as computer viruses, worms, Trojans, spyware etc.